I was a professional Captain here for many years and did not do too much 'hired bareboat' work.
However when I did the contract always clearly stated that the charterer was responsible for supplying my food and drink.
I fully expected to eat what they ate onboard and at least an offer to join them ashore. I also always offered to HELP cook or clean up.
Truthfully it was 'hit or miss' on the food part -- mostly fine but some fairly bizarre weeks too.
I never drank their alcoholic beverages or accepted drinks on shore -- except for way back in the 70's when the charter guests, crews and boats were very different - a very different era!
Overall it was a pretty hard job - I was the only one responsible 24/7 and everyone else was on full tilt vacation mode.